Problem: Before the previous stop there were 14 people riding on a train. 7 people ended up getting off at the stop. How many people are riding the train now?
Solution: The number riding the train now is the difference between the number who were riding and the number who got off at the previous stop. The difference is $14 - 7$ people on the train. $14 - 7 = 7$ people are on the train.